An example of the prior art of the present invention is a known particle image analyzer which includes a flow cell for converting a particle suspension flow into a flow surrounded by a sheath fluid, light irradiating means for irradiating the converted suspension flow with light, image sensing means for acquiring an image of the irradiated particles, image analyzing means for analyzing the acquired particle images, and a display means, wherein the image analyzing means includes a calculation means for measuring particle data relating to the surface area and circumferential length of each acquired particle image and calculating the circularity of the particle from the particle data, graph preparation means for preparing a histogram based on the particle diameter and particle frequency data and preparing a two-dimensional scattergram using two parameters corresponding to particle diameter and circularity for displaying on the display means, memory means for storing each acquired particle image, and a particle image recall means for collectively displaying particle images stored in the memory means on the display means (refer to U.S. Pat. No. 5,721,433).
Analyzing and measuring various kinds of information relating to particles has become increasingly important in recent years in manufacturing processes and quality management processes for various particle materials, such as fine ceramic particles, toners, pigments, cosmetic powders, food additives, and chemical agents.
Although particle shape and circularity or degree of agglutination and the like can be determined using conventional methods and apparatuses, other particle information, such as, for example, degree of particle irregularity and light attenuation rate cannot be determined.